April 22, 2009
More on the missing link (see previous post), Puijila darwini:
A “missing link” fossil of a new mammal species from Canada’s High Arctic rewrites the evolutionary story of seals. This prehistoric carnivore represents a new branch on a family tree, between an ancestor that walked on land and today’s sea-going seals and their relatives. It provides insight into what pinnipeds (true seals, sea lions and the walrus) looked like before they were adapted to hunting in the ocean. It also suggests a different centre of pinniped evolution from that of the prevailing theory. The fossil is 24 to 20 million years old and was found in the Haughton Crater on Devon Island. The research team is led by Dr. Natalia Rybczynski of the Canadian Museum of Nature.
April 21, 2009
OTTAWA – Scientists have found a “missing link” in the early evolution of seals from land mammals to the marine carnivores we see today.
Paleontologists working in the North have discovered a skeleton in an ancient Arctic lake bed that has given them a glance of the animal’s land-to-sea transition, which had been difficult to study because of a lack of fossil evidence.
The find offers the “first glimpse into the earliest stages of this important evolutionary transition,” lead researcher Natalia Rybczynski said.
It has also helped the team refute the prevailing theory that seals evolved on North America’s northwest shores, and suggests that their large eyes were adapted to hunt in dark Arctic winters, not low light deep sea diving.
“It changes our thinking about how and where the evolution of this animal took place,” said Rybczynski, a paleontologist at Carleton University in Ottawa.
Read the complete article by Michel Comte, Agence France-Presse, here.
The study will appear in the April 23 edition of the journal Nature.
Rybczynski, N., Dawson, M., & Tedford, R. (2009). A semi-aquatic Arctic mammalian carnivore from the Miocene epoch and origin of Pinnipedia Nature, 458 (7241), 1021-1024 DOI: 10.1038/nature07985
Update, 22 April, 2009.